FOOT AND MOUTH DISEASE 437 
tive disturbances, pharyngitis and pneumonia are complications - 
referred to mouth lesions. Septiceemia and pyemia sometimes occur. 
The duration of the disease in uncomplicated cases varies from 10 to 
20 days. -When complications occur either with the regular course 
or as sequels the duration becomes indefinite. The mortality varies 
with the severity of the attacks, the age and condition of the animals 
and the treatment. Ordinarily the mortality is not high, excepting in 
very young animals. 
Fic, 98. FOOT AND PASTERN REGION OF PIG SHOWING CHARACTERISTIC LESIONS (Kitt). 
Fig. 99. SECTION OF HOOFS SHOWING CLEAVAGE BETWEEN THE HORNY AND SENSITIVE 
soLeE (Zschokke.) 
Morbid anatomy. The characteristic lesions are the eruptions in 
the mouth, the interdigital spaces and in cows on the udder and teats. 
The eruptions consist of vesicles or blisters, varying in size from 
one to ten or more millimeters in diameter, containing at first a clear 
liquid which later becomes grayish in color. The thin layer of epi- 
dermis ruptures, sloughs off, leaving a raw, deeply reddened surface. 
The denuded and slightly depressed surfaces are soon recovered with 
epithelium. At first they present a brownish color which soon dis- 
appears. After the denuded areas are covered with epithelium the 
characteristics of the disease are lost. 
According to Zschokke the lesions on the tongue begin in the 
Stratum spinosum of the malpighian layer of epithelium. Often 
